Multispindle automatic lathes



Filed April 16, 1965 P 5', 6 I TOYOSUKE TSUDA 3,339,440

MULTISPINDLE AUTOMATIC LA'IHES 2 Sheets-Sheet 1 INVENTOR o osu ke Eudd,

ATTORNEY TOYOSUKE TSUDA MULTISPINDLE AUTOMATIC LATHES Sept. 5, 19617 I 2Sheets-Sheet 2 Filed April 16, 1965 16 :yJ'IIIIIIIIIIIIIIII IA 'I'IIIINVENTOR ATTORNEY United States Patent 3,339,440 MULTISPINDLE AUTOMATICLATHES Toyosuke Tsuda, Kariya-shi, Japan, assignor to Tsuda Iron WorksLtd., Kariya-shi, Aichi-ken, Japan, a corporation of Japan Filed Apr.16, 1965, Ser. No. 448,677 7 Claims. (Cl. 82-3) This invention relatesto multispindle automatic lathes and more particularly to lathes of theabove-described type in which means are provided to drive each spindleby an independent electric motor.

In multispindle automatic lathes of conventional structure hithertoemployed, the spindles thereof have been driven by a single electricmotor by way of a train of gears. Therefore, in the mulltispindleautomatic lathes of prior type, there has been the necessity of specialprovision of a drive gear casing to accommodate therein gears so as todrive the spindles by a single motor, and gears to be accommodatedtherein must be of high precision in order to minimize noises causedthereby and excessive wears thereof. Various other diflicultiesencountered with the lathe of the type of prior structure includetroublesome shifting of gears to attain desired speed variation andamong others it is most difficult to selectively vary the speed ofindividual spindles.

Therefore, it is the primary object of the present invention to providea multispindle automatic lathe of improved structure in which anindependent electric motor is provided for each of the spindles toseparately drive the same in order to dispense with the provision of anytoothed wheels for the driving of the spindles, thus eliminating thedifliculties resulting from the gear drive.

According to the present invention, there is provided a multispindleautomatic lathe comprising a motor mounting drum mounted for rotation ona shaft, a plurality of circumferentially spaced spindles journalled insaid drum, circumferentially spaced electric motors one for each spindlemounted in said drum in a manner to be radially spaced from saidspindles, and means to transmit the driving power from each motor to thecorresponding spindle.

Other objects and advantages of the present invention will becomeapparent from the following description with reference to theaccompanying drawings, in which:

FIG. 1 is a front elevational view of the multispindle automatic latheembodying the present invention;

FIG. 2 is a plan view of the lathe;

FIG. 3 is a side elevational view of the lathe; and

FIG. 4 is an enlarged vertical sectional view of part of the lathe.

Referring to the drawings, reference numeral 1 designates a motormounting drum of substantially U-shaped section, on the inner peripheralwall of which there are mounted a plurality of circumferentially spacedelectric motors 3 in a manner that each motor 3'is radially opposed by aspindle 2. A cone pulley 4 is firmly secured on the shaft of each motor3 and a cone pulley 5 is also firmly secured on the correspondingspindle 2 so that the driving power is transmitted from the motor 3 tothe spindle 2 through a transmission belt 6 passed about the pulleys 4and 5. A collet chuck 7 for holding a workpiece therein is providedatthe front end of each spindle 2. The collet chuck 7 is operated byadvancing and retracting movement of an actuating rod 11 caused by ahydraulic cylinder when the spindles 2 take a predetermined position atwhich they align with the hydraulic cylinder 10. The tool post of thelathe comprises tool holders 8 and a slidable carriage 9 therefor. Themotor mounting drum 1 is mounted on a rotary shaft 12 so that the drum 1can be rotated thereabout by drive means of any type well known in theart.

From the foregoing description, it will be understood that the uniquearrangement according to the present invention is quiteadvantageous inthat selection and control of normal rotation, reverse rotation andabrupt stopping of the spindles can freely electrically be effectedindependently of one another in a given cycle, and a suitablecombination of electric motors of different outputs can be provideddepending on a variety of works. Thus, in the multispindle automaticlathe of the present invention, selection of various numbers ofrevolutions and operations is far easier than with the lathe of the typedriven through a train of gears, and the operation thereof issubstantially noiseless because it is free from noises caused by toothedwheels.

Further advantages derived from the invention are ease of motor mountingduring replacement or repair of the motors and a low cost of manufacturebecause toothed wheels of high precision are not involved in theinventive lathe.

What is claimed is:

1. A multispindle automatic lathe comprising: a drum rotatably mountedon a single shaft; said drum being shallow cup-shaped with substantiallyU-shaped crosssection in substantially all planes passing through theaxis of said single shaft defining an interior, a closed end and an openend; a plurality of spindles circumferentially mounted for rotation onsaid drum within its interior; a separate motor associated with each ofsaid spindles and radially spaced outwardly from its correspondingspindle, and each of said motors being mounted on said drum within itsinterior and having an armature shaft; said armature shafts and saidspindles being mounted parallel to each other and parallel to saidsingle shaft; separate power transfer means consisting essentially offlexible endless drive members and cooperating drive wheels, for forminga direct driving connection between each of said armature shafts and thecorresponding spindle; each of said spindles having a terminal portionextending through the closed end of said drum, and a collet chuckmounted on said terminal portion outside of said drum.

2. The lathe of claim 1, said power transfer means being operable toselectively produce any one of a plurality of drive speed ratios betweenthe spindle and armature shaft of each spindle-motor combination.

3. The lathe of claim 2, said endless drive members constituting beltsand said drive wheels constituting conestepped vmultiple groove pulleys.

4. The device of claim 2, single actuator means stationarily mountedwith respect to said drum for selective successive alignment with eachof said collet chucks during rotation of said drum for individuallyselectively actuating said collet chucks one at a time.

5. The lathe of claim 4, a carriage; a plurality of tool holders mountedon said carriage; means for slidably mounting said carriage for movementtoward and away from said drum.

6. The lathe of claim 1, single actuator means stationarily mounted withrespect to said drum for selective successive alignment with each ofsaid collet chucks during rotation of said drum for individuallyselectively actuating said collet chucks one at a time.

7. The lathe of claim 1, a carriage; a plurality of tool holders mountedon said carriage; means for slidably mounting said carriage for movementtoward and away from said drum.

References Cited UNITED STATES PATENTS Davis 82-3 XR 5 Biewend 82-3Schurr 82-3 XR Drummond 82-3 XR Staples 82-3 XR McShirley 82-3 XR Hoern82-3 Cashman 82-3 XR HARRISON L. HINSON, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,339,440 September 5 1967 Toyosuke Tsuda It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

In the heading to the printed specification, after line 6, insert Claimspriority, application Japan, Dec. 28, 1.964,

Signed and sealed this 22nd day of October 1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

1. A MULTISPINDLE AUTOMATIC LATHE COMPRISING: A DRUM ROTATABLY MOUNTEDON A SINGLE SHAFT; SAID DRUM BEING SHALLOW CUP-SHAPED WITH SUBSTANTIALLYU-SHAPED CROSSSECTION IN SUBSTANTIALLY ALL PLANES PASSING THROUGH THEAXIS OF SAID SINGLE SHAFT DEFINING AN INTERIOR, A CLOSED END AND AN OPENEND; A PLURALITY OF SPINDLES CIRCUMFERENTIALLY MOUNTED FOR ROTATION ONSAID DRUM WITHIN ITS INTERIOR; A SEPARATE MOTOR ASSOCIATED WITH EACH OFSAID SPINDLES AND RADIALLY SPACED OUTWARDLY FROM ITS CORRESPONDINGSPINDLE, AND EACH OF SAID MOTORS BEING MOUNTED ON SAID DRUM WITHIN ITSINTERIOR AND HAVING AN ARMATURE SHAFT; SAID ARMATURE SHAFTS AND SAIDSPINDLES BEING MOUNTED PARALLEL TO EACH OTHER AND PARALLEL TO SAIDSINGLE SHAFT; SEPARATE POWER TRANSFER MEANS CONSISTING ESSENTIALLY OFFLEXIBLE ENDLESS DRIVE MEMBERS AND COOPERATING DRIVE WHEELS, FOR FORMINGA DIRECT DRIVING CONNECTION BETWEEN EACH OF SAID ARMATURE SHAFTS AND THECORRESPONDING SPINDLE; EACH OF SAID SPINDLES HAVING A TERMINAL PORTIONEXTENDING THROUGH THE CLOSED END OF SAID DRUM, AND A COLLET CHUCKMOUNTED ON SAID TERMINAL PORTION OUTSIDE OF SAID DRUM.